Metal-Organic Framework MIL-101: Synthesis and Photocatalytic Degradation of Remazol Black B Dye

Abstract

In the present paper, the synthesis of metal-organic framework MIL-101 and its application in the photocatalytic degradation of Remazol Black B (RBB) dye have been demonstrated. The obtained samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption/desorption isotherms at 77 K. It was found that MIL-101 synthesized under optimal conditions exhibited high crystallinity and specific surface area (3360 m2·g-1). The obtained MIL-101 possessed high stability in water for 14 days and several solvents (benzene, ethanol, and water at boiling temperature). Its catalytic activities were evaluated by measuring the degradation of RBB in an aqueous solution under UV radiation. The findings show that MIL-101 was a heterogeneous photocatalyst in the degradation reaction of RBB. The mechanism of photocatalysis was considered to be achieved by the electron transfer from photoexcited organic ligands to metallic clusters in MIL-101. The kinetics of photocatalytic degradation reaction were analyzed by using the initial rate method and Langmuir-Hinshelwood model. The MIL-101 photocatalyst exhibited excellent catalytic recyclability and stability and can be a potential catalyst for the treatment of organic pollutants in aqueous solutions.

Nitrogen compounds removal from oil-derived middle distillates by MIL-101(Cr) and its impact on ULSD production by hydrotreating

“…S3) through Bragg Law (~4.6 nm). Those values were in accordance to that previously reported by others [54]. As already mentioned, that reflection could be related to planes where water molecules were removed (thus, formation of CUS where NOC could be adsorbed) by MOF structure [54].…”

“…The isotherm of prepared MOF (as powder, Fig. S2) was similar to those already reported for materials prepared with alike H 2 O/H 2 BDC molar ratio (275) [54] where strong contribution from micropores (filled at P/P 0 < 0.3) was evidenced. However, in our case significant rise in adsorption at P/P 0~0 .8 accompanied by desorption branch hysteresis (absent in conventional MIL-101(Cr) [55]) pointed out to mesopores probably created by PO addition that promoted condensation reactions resulting in agglomerated particles.…”

“…Thus, it appeared that MIL-101(Cr) crystallinity was not importantly affected by using PO as mesoporosity inductor during materials synthesis. Interestingly, the (111) peak at approximately 1.7°(2Ɵ) unstable in moistened air (decreased intensity or disappearing) [54] has been related to water molecules removal (thus CUS formation) from MOF structure. As aforementioned, CUS on octahedral Cr 3+ trimers formed by dehydration could strongly contribute in NOC removal through their strong interaction with non-shared electron pairs in N moieties.…”

“…As aforementioned, CUS on octahedral Cr 3+ trimers formed by dehydration could strongly contribute in NOC removal through their strong interaction with non-shared electron pairs in N moieties. MIL-101(Cr) structure was stable (as identified by (111) plane preservation) in presence of both polar and nonpolar solvents (as ethanol and benzene, respectively [54]) at corresponding boiling temperature what is relevant during regeneration process as the adsorbent is submitted to drying (120°C) after acetone washing (see Sect. 2.4).…”

“…Bands at 271, 432, and 591 nm are characteristic of MIL-101(Cr) [54], Figure S5. UV absorption was due to n ?…”